WITH Base AS (
SELECT
DATEDIFF(SECOND, LAG(BLOCK_TIMESTAMP) OVER (ORDER BY BLOCK_TIMESTAMP), BLOCK_TIMESTAMP ) AS difference_time
FROM
polygon.core.fact_blocks
WHERE BLOCK_TIMESTAMP::DATE >= '2022-01-01'
AND NETWORK = 'mainnet'
ORDER BY BLOCK_NUMBER)
SELECT
AVG(difference_time) AS average_time
FROM
Base